Horses that are exposed to cold, wet weather or worked after becoming sick, frequently suffer from pneumonia, pericarditis, gastro-enteritis and other diseases. Such complications should be given prompt treatment.
It is very advisable to give a protective serum to horses that are shipped or transported long distances, and exposed to the disease in sale or transfer stables.
GLANDERS, FARCY.—This is a contagious and infectious disease of solipeds that is characterized by the formation of nodules and ulcers on the skin, nasal mucous membrane and lungs.
Although glanders is one of the oldest of animal diseases, it was not until 1868 that its contagious character was demonstrated. The disease is widely distributed. It became more prevalent in the United States after the Civil War. The vigorous control measures practised by the State and Federal health officers have greatly decreased the percentage of animals affected with glanders. At the present time the disease is more often met with in the large cities than in the agricultural sections of the country.
[Illustration: FIG. 114.—Bacillus mallei.]
The specific cause of glanders is the Bacillus mallei (Fig. 114). This microorganism was discovered in 1882. It is present in the discharges from the nasal mucous membrane and the ulcers. These discharges may become deposited upon the feed troughs, mangers, stalls, harness, buckets, watering troughs, drinking fountains and attendants' hands and clothing. Healthy horses living in the same stable with the glandered animals may escape infection for months. It is usually the diseased animal's mate, or the one standing in an adjoining stall, that is first affected. Catarrhal diseases predispose animals to glanders, as the normal resistance of the mucous membranes is thereby reduced. The most common routes by which the germ enters the body are by way of the digestive and respiratory tracts. It may enter the body through the uninjured mucous membranes of the respiratory tract and genital organs, or through wounds of the skin.
The period of incubation may be from a few to many days.
The symptoms may be acute or chronic in nature. The acute form pursues a rapid course. It is frequently seen in mules and asses, and it may develop from the subacute or chronic form in horses. When the disease is acute, the animal has a fever, is stupid, does not eat, and may have a diarrhoea. In this form the lymphatic glands suppurate, the animal loses flesh rapidly and dies in from one to two weeks.
[Illustration: FIG. 115.—Nasal septum showing nodules and ulcers.]
The chronic form is the most common. It develops slowly and lasts for years. The early symptoms of the disease (chilling and fever) usually escape notice. The first visible symptom is a nasal discharge of a dirty white color from one or both nostrils. This is usually scanty at first, and intermittent, but later becomes quite abundant. The discharge is very sticky, and adheres to the hair and skin. The most frequent seat of the disease is in the respiratory organs, lymph glands and skin. Nodules and ulcers appear on the nasal mucous membrane (Fig. 115), but they may be so high up as to escape notice. The ulcers are very characteristic of the disease. They are angry looking, with ragged, raised margins, and when they heal leave a puckered scar. The submaxillary glands may be enlarged, and at first more or less hard and painful, but later they become nodular and adhere to the jaw or skin. Nodules and ulcers may form on the skin over the inferior wall of the abdomen and the inside of the hind limbs and are known as "farcy buds." Lymphatic vessels near these buds become swollen and hard. The animal loses flesh rapidly, does not withstand hard work, and the limbs usually swell.